EP0560652B1 - Control device for above knee prosthesis - Google Patents

Description

The present invention relates to a hydraulic regulation device for the walking of femoral amputees.

We know that the stump of these amputees is housed in an element of complementary shape, called "socket", articulated itself on an element of artificial leg. These two organs are also joined, generally, by a hydraulic shock absorber, which has a function of regulating the walking of the amputee. For this purpose, a rod of a worse tone of the damper is articulated on the socket, while the cylindrical body of the damper is articulated on the leg element (or vice versa), and the circulation of the hydraulic fluid in this shock absorber is designed so as to provide assistance to the person wearing the device, both in the extension phase and in the flexion phase of the walk, in particular by offering a strong resistance to flexion in all walking situations, especially in the event of a false step.

FR-A-1 565 589 describes, for example, a prosthesis joint provided with a hydraulic return device with preponderant damping in one direction and blocking for a movement speed greater than a predetermined value. This articulation comprises an active cylinder containing a piston displaced during the movement of the articulation and an elastic energy accumulator, linked together by communications, at least one of which comprises a non-return valve, while another at the less has a valve dynamically driven to shutter on its seat by a movement of hydraulic fluid at a speed greater than a predetermined value.

It is this type of hydraulic gait control device that the present invention is interested in and it aims more precisely to provide constant and controlled braking in the event of the fall of the person wearing the device.

A first object of the invention is therefore to propose a device for regulating the walking of the femoral amputees which opposes constant and controlled braking to the possible fall of the patient.

Another object of the invention is to propose a hydraulic regulation device of this type, in which the pressure of the hydraulic fluid, from which the braking takes place, can be adjusted taking into account the physical capacities of the person wearing the device.

To this end, the subject of the invention is a device for hydraulic regulation of the walking of the femoral amputees, of the type of hydraulic shock absorbers, comprising a first piston moving in a cylinder by entraining a hydraulic fluid, a first circulation circuit of this hydraudic fluid opening through at least a first orifice in a flat part of one end of the cylinder and communicating with the opposite end of this cylinder, a reservoir of hydraulic fluid under pressure communicating with this first circuit, this reservoir comprising a movable wall constituting a second piston, urged by an elastic return means, the first udder being intended to be articulated on a socket covering the stump of an amputee, while the cylinder body can be articulated on an artificial leg element (or vice versa) ), the leg element itself being articulated on the socket, this device further comprising a so upape, requested by the hydraulic fluid against an elastic return means when the pressure of the hydraulic fluid, under the request of the first piston, reaches a predetermined threshold, following an involuntary movement of the amputee, this device being characterized in that the valve is capable of closing the first orifice of the first hydraulic circuit, in that a second hydraulic circuit partially independent of the first comprises a conduit, constituting a controlled leakage conduit, which opens below the valve, and that a means of control is provided to move the valve so as to bring or not opposite a light of this valve and the orifice of the corresponding conduit of controlled window.

The valve control means may advantageously drive the latter in rotation.

Preferably, the elastic return means urging the valve will be adjustable, so as to be able to adapt the device to the degree of autonomy of the amputee.

Preferably also, a controllable system for blocking the valve in the closed position of the first orifice will be provided, so as to allow the amputee to intentionally block this valve, by blocking or not closing the second orifice for controlled passage of the fluid. hydraulic. When this second opening is left free, a braking movement will be opposed to the displacements of the piston and this may be useful for the amputee, for example, in the case of a staircase descent. When the first and second orifices are both closed, the piston will be locked in position in the compression phase.

• Figure 1 : pendant la phase de traction du piston du dispositif de régulation hydraulique, au cours d'une marche normale de l'amputé ;
• Figure 2 : pendant la phase de compression du piston du dispositif, également au cours d'une marche normale de l'amputé ;
• Figure 3 : dans le cas d'une perte d'équilibre de l'amputé, à la suite d'un mouvement involontaire de celui-ci ;
• Figure 4 : après blocage partiel volontaire du dispositif, par exemple pour assister l'amputé se déplaçant dans un escalier ;
• Figure 5 : après blocage volontaire complet du dispositif ;
• La figure 6 est une vue partielle de dessus de la soupape du dispositif, dans la position des figures 1,2 et 3 ;
• La figure 7 est une vue analogue à la figure 6, lorsque le dispositif est dans la position de la figure 4;
• La figure 8 est une vue analogue aux figures 6 et 7, dans la position occupée par le dispositif sur la figure 5.

The attached schematic drawings, which are not limiting, illustrate an embodiment of the invention. All the figures of the drawings, with the exception of FIG. 6, are views in axial section of the device, in different phases of use, namely:

• Figure 1: during the traction phase of the piston of the hydraulic regulation device, during normal operation of the amputee;
• Figure 2: during the compression phase of the device piston, also during normal operation of the amputee;
• Figure 3: in the case of a loss of balance of the amputee, following an involuntary movement of the latter;
• Figure 4: after voluntary partial blocking of the device, for example to assist the amputee moving on a staircase;
• Figure 5: after complete voluntary blocking of the device;
• Figure 6 is a partial top view of the valve of the device, in the position of Figures 1,2 and 3;
• Figure 7 is a view similar to Figure 6, when the device is in the position of Figure 4;
• FIG. 8 is a view similar to FIGS. 6 and 7, in the position occupied by the device in FIG. 5.

We will first refer to Figures 1 and 2.

As can be seen, the device shown comprises a damper body 1, one end of which is intended to be articulated by an axis 2 on the artificial leg (not shown) of a femoral amputee. In the central part of this device is formed a first cylinder 3 containing a hydraulic fluid 4 and in which a piston 5 moves, the rod 6 of which projects outside the body 1 and is articulated at its end by an axis 7 on the 'socket (not shown) in which is housed the stump of the amputee. A reverse arrangement could naturally be adopted, with the body 1 articulated on the socket and the rod 6 articulated on the artificial leg. The socket and the artificial leg are naturally hinged together in the usual way.

A second cylinder 8, of annular section, is arranged concentrically with the cylinder 3 and can communicate with the latter, on the one hand, at its upper part, by orifices 9 formed in its side wall, on the other hand, at its lower part, by conduits 10,26,16 opening into the bottom of the cylinder 3, by a manifold 12 and by a conduit 11, opening into the bottom of the cylinder 8.

A valve 21, urged by the hydraulic fluid 4, against a return spring 27, which urges its rod 13, makes it possible to close off the orifices through which the conduits 16, 10 open into the bottom of the cylinder 3 A screw 14, controllable from the outside of the device, makes it possible to move a movable disc 15 on which the spring 27 bears, in order to adjust the tension of the latter and the pressure that it exerts on the valve 21.

The valve 21 can be driven in rotation by a movable pin in rotation or eccentric 17, which is engaged in a recess 18 of the stem 13 of the valve and which projects laterally outside the device.

A controlled leakage pipe 10, communicating with the manifold 12, opens into the bottom of the cylinder 3 through an orifice 19 (see FIG. 6), plumb with which a light 20 can be brought in the form of a circular arc, formed in the valve, so that, depending on the position of the valve 21, the conduit 10 and therefore the manifold 12 may or may not communicate with the cylinder 3, even when the valve is applied against the bottom of the cylinder.

The manifold 12 finally communicates via conduits 22 with a cylindrical reservoir 23, of circular section, arranged concentrically with the cylinder 8, the upper part of which is constituted by a movable annular element 24, forming a piston, biased by a spring 25, which, at its other end bears against the upper part of the body 1.

The operation of this device is as follows.

In the normal walking position of a person with an amputated femur, whose stump is housed in a socket articulated on an artificial leg, with a hydraulic regulation device according to the invention interposed between the socket and the leg, the valve 21 does not rest on the bottom of cylinder 3 (Figures 1 and 2). The hydraulic fluid, under the bias of the piston 5, therefore circulates normally, in a manner known per se, in the direction indicated by the arrows, between the cylinders 3 and 8, on either side of the piston 5, and between these cylinders and the reservoir 23, both in the phase of compression of the hydraulic fluid in the cylinder 3 (FIG. 2) and in the phase of traction of the piston 5 (FIG. 1). As indicated above, part of the hydraulic fluid borrows the conduit 10 for controlled leakage.

If, following a false movement of the amputee, for example a fall, the speed of movement of the piston 5 becomes significant, the valve 21, under the effect of the pressure and the speed of the fluid, is pressed against the bottom of the cylinder 3, closing the orifice of the conduits 16. The orifice 19 of the controlled leakage conduit 10 is however in coincidence with the port 20 of the valve, and the hydraulic fluid can therefore continue to use the conduit 10 thereby braking the descent of the piston 5. The pressure from which the valve 21 is pressed against the bottom of the cylinder 3 can be adjusted and easily adapted to the degree of autonomy of the person amputated. acting on the screw adjustment 14.

If, in order to exercise certain movements, this person wishes to partially block the device, for example to descend a staircase, leaving only the controlled leakage conduit 10 accessible to the hydraulic fluid (FIG. 4), it will suffice to actuate the eccentric 17 in an appropriate direction, for example clockwise, to lower the valve 21 and rotate it simultaneously, but leaving the orifice 19 of the conduit 10 in communication with the port 20 of the valve.

Finally, in the case where the amputee wants to completely block the device (Figure 5), he will actuate the eccentric 17 in the opposite direction to the previous case (case of Figure 4), to lower the valve 21 and cause it to close simultaneously the orifice 19 of the controlled leakage pipe 10 (FIG. 6), the extension phase always remaining possible thanks to the pipe 25.

The device according to the invention therefore provides, in a simple form, significant improvements to the hydraulic regulation devices of the walking of the femoral amputees.

Claims (6)

1. A device for hydraulically controlling the walking of femoral amputees, of the hydraulic shock absorber type, comprising a first piston (5) moving in a cylinder (3) and displacing a hydraulic fluid, a first circuit (8, 9, 10, 11, 16) for the circulation of this hydraulic fluid opening via at least a first orifice in a flat part of one end of the cylinder (3) and communicating with the opposite end of this cylinder, a compressed hydraulic fluid tank (23) communicating with this first circuit, this tank comprising a movable wall (24) constituting a second piston and loaded by a resilient return means (25), the first piston (5) being designed to be articulated to a casing capping the stump of an amputee, while the body (1) of the cylinder may be articulated to an artificial leg member (or vice versa), this leg member itself being articulated to the casing, this device further comprising a valve (21) loaded by the hydraulic fluid counter to a resilient return means (27) when the pressure of the hydraulic fluid, under the loading of the first piston (5), reaches a predetermined threshold, following an involuntary movement on the part of the amputee, this device being characterised in that the valve (21) is capable of sealing the first orifice of the first hydraulic circuit, in that a second hydraulic circuit, partially independent of the first, comprises a duct (10) constituting a controlled escape duct which opens below the valve (21) and in that a control means (17) is provided to move the valve (21) in such a way as to bring into position opposite each other, or not, a slot (20) in this valve and the corresponding orifice (19) of the controlled escape duct (10).
2. A device according to claim 1, characterised in that the circuit used by the hydraulic fluid to pass either side of the piston comprises a second annular cylinder (8) concentric with the first cylinder (3).
3. A device according to either one of claims 1 and 2, characterised in that the tank (23) has an annular section and is concentric with the cylinder (3).
4. A device according to any one of claims 1 to 3, characterised in that the control means (17) drives the valve (21) in rotation.
5. A device according to claim 4, characterised in that the control means (17) of the valve (21) permits the application thereof against the orifices of the first and second hydraulic circuits.
6. A device according to any one of claims 1 to 5, characterised in that the tension of the resilient return means (27) of the valve (21) is adjustable.

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